Libby is an American physicist with the ability to transform matter. She spends her early life researching degenerative diseases, hoping to find a magical cure for the illness that took her older sister, Katherine. Anxious and a perfectionist, she is frequently underestimated by her peers who view her insecurities as a weakness. Despite her doubts, she possesses extraordinary magical power and adheres to a rigid moral code.

Nicolás, known as Nico, is a wealthy Cuban physicist whose abilities include levitation, incandescence, and shapeshifting matter. He approaches his magic with a physical, straightforward style that matches his relatively honest personality. Outside the classroom, he dedicates his energy to protecting his narcoleptic roommate Gideon from exploitation. He accepts the Society's invitation primarily to access archives that might secure Gideon's permanent safety.

Reina is a Japanese naturalist capable of rapidly growing plants, though she actively avoids using her powers because nature drains her physical life force. Raised in secret as the illegitimate daughter of a wealthy family, she studies mythology to distance herself from her abilities. She is a solitary, blunt young woman who dislikes group dynamics and only joins the Society for the promise of reading ancient, lost texts.

Tristan is a Black English illusionist trying to build an ordinary, successful life to escape the shadow of his criminal father, Adrian Caine. Employed by billionaire James Wessex, he hides his true magical ability—seeing through magical illusions and perceiving reality itself. He is highly observant and cynical, using his wit and meticulous nature to hide deep-seated anxiety and self-loathing.

Callum is a wealthy South African empath who can read and actively influence the emotions of those around him. He uses this power to manipulate situations to his advantage, finding normal interactions boring. Possessing no standard moral code, he views his peers clinically and exploits their insecurities without hesitation. He operates under the belief that everyone is ultimately driven by selfish hunger.

Parisa is a telepath who studied in Paris after escaping an abusive family in Tehran. She utilizes her extraordinary physical beauty to distract targets, slipping into their minds to extract information while their defenses are lowered. Confident and highly calculating, she views human interaction as a strategic game where she holds the upper hand.

Atlas is a Caretaker of the Alexandrian Society, tasked with selecting six exceptional medeians every decade for potential initiation. A polite British man favoring tweed suits, he serves as a lecturer and guide to the candidates. He directs their studies in magical philosophy and physics while keeping the true nature of their upcoming trials closely guarded.

Dalton is a researcher at the Alexandrian Society who successfully passed initiation a decade prior. His specialty is animation, allowing him to construct highly lifelike illusions. He maintains a quiet, elegantly composed demeanor while overseeing the candidates' daily activities in the sentient house, though he hides deep personal trauma regarding his own initiation process.

Ezra is Libby's quiet, constantly snacking boyfriend whom she met during her studies at the New York University of Magical Arts. He expresses consistent worry regarding Libby's safety within the Alexandrian Society. His protective nature sometimes conflicts with her growing desire for independence and self-reliance.

Gideon is Nico's best friend and roommate, the son of a mermaid and a satyr. He is a human-like creature with narcolepsy and the unique ability to walk through dreams. Because his mother continually attempts to exploit his dream-walking for criminal purposes, he relies on Nico's magical wards to stay hidden.

Maximilian, often called Max, is a shapeshifter who shares an apartment with Nico and Gideon. He frequently spends his time in the form of a black Labrador Retriever and provides a stabilizing, friendly presence in Nico's life outside of his academic rivalries.

James Wessex is a billionaire venture capitalist based in London who aggressively opposes the Alexandrian Society. He employs Tristan Caine, treating him as an unofficial heir, and utilizes his immense wealth to coordinate breaches against the Society's magical defenses.

Eden is the daughter of billionaire James Wessex and is engaged to Tristan Caine. Her relationship with Tristan serves as a core component of his meticulously planned upward mobility in London society.

Adrian Caine is a notorious crime lord and the abusive father of Tristan. His criminal legacy is the primary reason Tristan works so hard to establish a legitimate, successful life in high society.

Eilif is a mermaid and Gideon's volatile mother. She operates as a criminal who travels across magical boundaries, continually hunting for her son so she can exploit his dream-walking abilities for her illicit jobs.

Aiya is a successful researcher and member of the Alexandrian Society who underwent initiation in the same class as Dalton Ellery. She uses the knowledge gained from the archives to secure real-world political influence and answers Reina's questions about the Society's history.

Katherine is Libby's older sister who died from a degenerative disease when Libby was thirteen. Her tragic passing fundamentally shaped Libby's character, driving her relentless pursuit of magical physics.